As technical literature in this field, Japanese Unexamined Patent Publication No. H6-93546 is known. In this literature, a glass chopped strand mat is described which is manufactured by spraying a binder onto glass chopped strands deposited in a sheet shape, heating and melting the binder, and then allowing the binder to cool and solidify, thereby binding the glass chopped strands. In a method for manufacturing the glass chopped strand mat, short glass chopped strands having a length of 3 cm or greater and smaller than 8 cm and long glass chopped strands having a length of 8 cm or greater and smaller than 15 cm are uniformly dispersed and are thereafter fixed by the binder.